SIST EN 61280-4-4:2006
(Main)Fibre optic communication subsystem test procedures -- Part 4-4: Cable plants and links - Polarization mode dispersion measurement for installed links
Fibre optic communication subsystem test procedures -- Part 4-4: Cable plants and links - Polarization mode dispersion measurement for installed links
This part of IEC 61280 provides uniform methods of measuring polarization mode dispersion (PMD) of single-mode installed links. An installed link is the optical path between transmitter and receiver, or a portion of that optical path. These measurements may be used to assess the suitability of a given link for high bit rate applications or to provide insight on the relationships of various related transmission attributes.
Prüfverfahren für Lichtwellenleiter-Kommunikationsuntersysteme -- Teil 4-4: Kabelnetze und Übertragungsstrecken - Messung der Polarisationsmodendispersion von installierten Übertragungsstrecken
Procédures d'essai des sous-systèmes de télécommunication à fibres optiques -- Partie 4-4: Installation de câbles et liens - Mesure de la dispersion de mode polarisation pour les liaisons installées
La présente partie de la CEI 61280 fournit des méthodes uniformes de mesure de la dispersion de mode de polarisation (PMD) de liaisons unimodales installées. Une liaison installée est le chemin optique entre l'émetteur et le récepteur ou une partie de ce chemin optique. Ces mesures peuvent être utilisées afin d'évaluer si une liaison donnée est adaptée à des applications à débit binaire élevé ou pour connaître les relations entre différents attributs d'une transmission.
Postopki preskušanja optičnega komunikacijskega podsistema – 4-4. del: Kabelske oblike in povezave – Meritve polarizacijske razpršitve v vgrajenih povezavah (IEC 61280-4-4:2006)
General Information
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Standards Content (Sample)
SLOVENSKI SIST EN 61280-4-4:2006
STANDARD
julij 2006
Postopki preskušanja optičnega komunikacijskega podsistema – 4-4. del:
Kabelske oblike in povezave – Meritve polarizacijske razpršitve v vgrajenih
povezavah (IEC 61280-4-4:2006)
Fibre optic communication subsystem test procedures – Part 4-4: Cable plants and
links – Polarization mode dispersion measurement for installed links (IEC 61280-4-
4:2006)
ICS 33.180.01 Referenčna številka
SIST EN 61280-4-4:2006(en)
© Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljeno
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EUROPEAN STANDARD
EN 61280-4-4
NORME EUROPÉENNE
April 2006
EUROPÄISCHE NORM
ICS 33.180.01
English version
Fibre optic communication subsystem test procedures
Part 4-4: Cable plants and links -
Polarization mode dispersion measurement for installed links
(IEC 61280-4-4:2006)
Procédures d'essai des sous-systèmes Prüfverfahren für Lichtwellenleiter-
de télécommunication à fibres optiques Kommunikationsuntersysteme
Partie 4-4: Installation de câbles et liens - Teil 4-4: Kabelnetze
Mesure de la dispersion de mode und Übertragungsstrecken -
polarisation pour les liaisons installées Messung der
(CEI 61280-4-4:2006) Polarisationsmodendispersion
von installierten Übertragungsstrecken
(IEC 61280-4-4:2006)
This European Standard was approved by CENELEC on 2006-02-01. CENELEC members are bound to comply
with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard
the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the Central Secretariat or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CENELEC member into its own language and notified
to the Central Secretariat has the same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Cyprus, the Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Central Secretariat: rue de Stassart 35, B - 1050 Brussels
© 2006 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 61280-4-4:2006 E
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EN 61280-4-4:2006 - 2 -
Foreword
The text of document 86C/683/FDIS, future edition 1 of IEC 61280-4-4, prepared by SC 86C, Fibre optic
systems and active devices, of IEC TC 86, Fibre optics, was submitted to the IEC-CENELEC parallel vote
and was approved by CENELEC as EN 61280-4-4 on 2006-02-01.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2006-12-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2009-02-01
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 61280-4-4:2006 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standards indicated:
IEC 60793-1-48 NOTE Harmonized as EN 60793-1-48:2003 (not modified).
IEC 61290-11-1 NOTE Harmonized as EN 61290-11-1:2003 (not modified).
IEC 61290-11-2 NOTE Harmonized as EN 61290-11-2:2005 (not modified).
__________
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- 3 - EN 61280-4-4:2006
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
NOTE Where an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD
applies.
Publication Year Title EN/HD Year
1) 2)
IEC 60793-1-44 - Optical fibres EN 60793-1-44 2002
Part 1-44: Measurement methods and
test procedures - Cut-off wavelength
1)
Undated reference.
2)
Valid edition at date of issue.
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NORME CEI
INTERNATIONALE
IEC
61280-4-4
INTERNATIONAL
Première édition
STANDARD
First edition
2006-02
Procédures d'essai des sous-systèmes
de télécommunication à fibres optiques –
Partie 4-4:
Installation de câbles et liens –
Mesure de la dispersion de mode polarisation
pour les liaisons installées
Fibre optic communication subsystem
test procedures –
Part 4-4:
Cable plants and links –
Polarization mode dispersion measurement
for installed links
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microfilms, sans l'accord écrit de l'éditeur. the publisher.
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Pour prix, voir catalogue en vigueur
For price, see current catalogue
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61280-4-4 IEC:2006 – 3 –
CONTENTS
FOREWORD.7
1 Scope.11
2 Normative references .13
3 Symbols and abbreviated terms.13
4 Background on PMD properties .15
5 Measurement methods .17
5.1 Methods of measuring PMD.17
5.2 Reference test method .25
6 Apparatus.25
6.1 Light source and polarizers .25
6.2 Input optics .27
6.3 Cladding mode stripper .27
6.4 High-order mode filter.27
6.5 Output positioner.27
6.6 Output optics.27
6.7 Detector .29
6.8 Computer .29
6.9 Means to reduce the effects of amplified spontaneous emission .29
7 Sampling and specimens.29
8 Procedure .29
9 Calculation or interpretation of results .29
10 Documentation .31
10.1 Information required for each measurement .31
10.2 Information to be available .31
11 Specification information .31
Annex A (normative) Fixed analyzer method .33
Annex B (normative) Stokes parameter evaluation method .47
Annex C (normative) Interferometric method.61
Annex D (normative) Stokes parameter evaluation method using back-reflected light .81
Annex E (normative) Modulation phase-shift method.85
Annex F (normative) Polarization phase shift method.107
Annex G (informative) PMD determination by Method C.123
Bibliography.131
Figure A1 – Block diagrams for fixed analyzer .33
Figure A2 – Example of the R-function for the fixed analyzer method.37
Figure A3 – PMD by Fourier analysis .43
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61280-4-4 IEC:2006 – 5 –
Figure B1 – Block diagram for Method B using a narrowband (tuneable laser) source.47
Figure B2 – Block diagram for Method B using a broadband (ASE) source.47
Figure C1 – Generic set-up for Method C (INTY).61
Figure C2 – Schematic diagram for Method C (TINTY).63
Figure C3 – Typical data obtained by Method C (TINTY).67
Figure C4 – Schematic diagram for Method C (GINTY) .69
Figure C5 – Typical random-mode-coupling data obtained by Method C (GINTY) .75
Figure C6 – Typical mixed-mode-coupling data obtained by Method C (GINTY) .77
Figure D1 – Layout for Method D .81
Figure E1 – Basic apparatus .85
Figure E2 – Apparatus layout for polarization modulation.93
Figure E3 – Mueller states on Poincaré sphere .99
Figure E4 – DGD versus wavelength.101
Figure E5 – DGD in histogram format .103
Figure F1 – Block diagram for Method F (polarization phase shift method).107
Figure F2 – DGD versus wavelength for a random mode coupling device .115
Table E1 – Example of Mueller set.99
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61280-4-4 IEC:2006 – 7 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
FIBRE OPTIC COMMUNICATION SUBSYSTEM
TEST PROCEDURES –
Part 4-4: Cable plants and links –
Polarization mode dispersion measurement
for installed links
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
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with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
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between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
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5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
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6) All users should ensure that they have the latest edition of this publication.
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expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61280-4-4 has been prepared by subcommittee 86C: Fibre optic
systems and active devices, of IEC technical committee 86: Fibre optics.
The text of this standard is based on the following documents:
FDIS Report on voting
86C/683/FDIS 86C/695RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
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61280-4-4 IEC:2006 – 9 –
IEC 61280 consists of the following parts under the general title Fibre optic communication
1)
subsystem test procedures :
2)
Part 1: General communication subsystems
3)
Part 2: Digital systems
4)
Part 4: Cable plant and links
Part 3 is in preparation.
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in the
data related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
___________
1)
The general title of the IEC 61280 series has changed. Previous parts were published under the general title
Fibre optic communication subsystem basic test procedures
2) The title of Part 1 has changed. Parts 1-1 and 1-3 were published under the title Test procedures for general
communication subsystems.
3) The title of Part 2 has changed. Parts 2-1, 2-2, 2-4 and 2-5 were published under the title Test procedures for
digital systems.
4) The title of Part 4 has changed. Part 4-2 was published under the title Fibre optic cable plant.
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61280-4-4 IEC:2006 – 11 –
FIBRE OPTIC COMMUNICATION SUBSYSTEM
TEST PROCEDURES –
Part 4-4: Cable plants and links –
Polarization mode dispersion measurement
for installed links
1 Scope
This part of IEC 61280 provides uniform methods of measuring polarization mode dispersion
(PMD) of single-mode installed links. An installed link is the optical path between transmitter
and receiver, or a portion of that optical path. These measurements may be used to assess
the suitability of a given link for high bit rate applications or to provide insight on the
relationships of various related transmission attributes. The principles of this document are
aligned with those of the optical fibre and optical fibre cable test method, IEC 60793-1-48 (see
Bibliography), which focuses on aspects related to the measurement of factory lengths.
Instead, this document focuses on the measurement methods and requirements for measuring
long lengths that might be installed – and that might also include other optical elements, such
as amplifiers, DWDM components, multiplexers, etc.
PMD is a statistical parameter. The reproducibility of measurements depends on the particular
5)
method, but is limited also by the PMD level of the link. Gisin [3] derived a theoretical limit to
this reproducibility, by assuming an infinite range of measured wavelengths and ideal
measurement conditions.
NOTE 1 Test methods for factory lengths of optical fibres and optical fibre cables are given in IEC 60793-1-48.
NOTE 2 Test methods for optical amplifiers are given in IEC 61290-11-1 and IEC 61290-11-2.
NOTE 3 Test methods for passive optical components are given in IEC 61300-3-32.
NOTE 4 Guidelines for the calculation of PMD for links that include components such as dispersion compensators
or optical amplifiers are given in IEC 61282-3.
With the exception of Method D, all methods in this document may be used to measure the
PMD in the gain band of links that include pumped optical amplifiers. For these links,
amplified spontaneous emission (ASE) noise can generate depolarized spectral energy in the
neighbourhood of the measurement wavelength. This will, in general, reduce the accuracy of
the measurement. For Methods A, B, C, E and F, this effect can be moderated by
implementing an optical or electrical filter at the receive end. However, optical filtering will not
remove the ASE right under the signal spectrum. The accuracy will then be limited by a lower
degree of polarization (DOP), if the spectral width of the filter cannot be sufficiently reduced
as with a broadband source. Lower DOP may require the signal to be integrated longer to be
meaningful or the result will become too noisy and interpretation will be erroneous.
None of the methods is suitable for measuring the PMD of links with polarization dependent
loss (PDL) in excess of 10 dB. Links with PDL values less than 1 dB can be measured with
reasonable accuracy. Measurement accuracy may be compromised by the presence of PDL in
excess of 1 dB.
___________
5)
Figures in square brackets refer to the bibliography.
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61280-4-4 IEC:2006 – 13 –
2 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition
of the referenced document (including any amendments) applies.
IEC 60793-1-44: Optical fibres – Part 1-44: Measurement methods and test procedures – Cut-
off wavelength
3 Symbols and abbreviated terms
c Velocity of light in vacuum (299792458 m/s)
h Coupling length
L Length of the link
t Optical source coherence time (Method C)
c
δλ Wavelength increment (step size)
δν Optical frequency increment (step size)
Δλ Optical source spectral width or linewidth (FWHM unless noted otherwise)
Δθ Rotation angle on Poincaré sphere
δτ Differential arrival times of different polarization components.
δτ Minimum δτ value that can be measured
min
Δτ Differential group delay value
<Δτ> Average DGD over a wavelength range or PMD value
average
2 1/2
<Δτ > RMS DGD over a wavelength range or PMD value
RMS
Δτ Maximum δτ value that can be measured
max
Δω Angular frequency variation in Method B
λ Test wavelength used to measure PMD
λ Central wavelength of the light source
0
v Optical light frequency
σ Second moment of Fourier transform data
R
σ RMS width of the squared autocorrelation envelope
0
σ RMS width of the squared cross-correlation envelope
x
σ RMS width of interferogram
ε
ω Angular optical frequency
ASE Amplified spontaneous emission
DGD Differential group delay
DOP Degree of polarization
DUT Device under test
FA Fixed analyzer
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61280-4-4 IEC:2006 – 15 –
FET Field effect transistor
FWHM Full-width half-maximum
GINTY General interferometric analysis
I/O Input-output
JME Jones matrix eigenanalysis
LED Light emitting diode
MPS Modulation phase shift
PDL Polarization dependent loss
PIN (diode) Positive insulated negative
PMD Polarization mode dispersion
PPS Polarization phase shift
PSA Poincaré sphere analysis
PSP Principal SOP
RBW Resolution bandwidth
RMS Root mean-square
SOP State of polarization
SPE Stokes parameter evaluation
TINTY Traditional interferometric analysis
4 Background on PMD properties
PMD causes an optical pulse to spread in the time domain. This dispersion could impair the
performance of a telecommunications system. The effect can be related to differential phase
and group velocities and corresponding arrival times, δτ, of different polarization components
of the signal. For a sufficiently narrowband source, the effect can be related to a differential
group delay (DGD), Δτ, between pairs of orthogonally polarized principal states of polarization
(PSP) at a given wavelength. For broadband transmission, the delays bifurcate and result in
an output pulse that is spread out in the time domain. In this case, the spreading can be
related to the root-mean square (RMS) of DGD values.
In long fibre spans, DGD varies randomly both in time and wavelength since it depends on the
details of the birefringence along the entire fibre length. It is also sensitive to time-dependent
temperature and mechanical perturbations on the fibre. For this reason, a useful way to
characterize PMD in long fibres is in terms of the expected value, <Δτ>, or the mean DGD
over wavelength. In principle, the expected value <Δτ> does not undergo large changes for a
given fibre from day to day or from source to source, unlike the parameters δτ or Δτ. In
addition, <Δτ> is a useful predictor of transmission performance.
The term "PMD" is used both in the general sense of two polarization modes having different
group velocities (one having the fastest velocity and corresponding earliest arrival time and
the other the slowest velocity and corresponding latest arrival time, the difference between
the two arrival times being the DGD), and in the specific sense of the expected value <Δτ>.
The latter gives us the strict definition of PMD for the purposes of this document. The DGD Δτ
or pulse broadening δτ can be averaged over wavelength, yielding <Δτ> , or frequency,
λ
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61280-4-4 IEC:2006 – 17 –
yielding <Δτ> , or time, yielding <Δτ> , or temperature, yielding <Δτ> . For most purposes, it
ν t T
is not necessary to distinguish between these various options for obtaining <Δτ>.
(1a)
PMD = Δτ
AVG
The expression in Equation (1a) is sometimes called the linear average of the DGD values. It
is reported for the purposes of specifying optical fibre cables and many other components.
Another metric, the RMS of the DGD values is also reported by some measurement
instruments, particularly those based on Method C. It is defined as:
1/ 2
2
(1b)
PMD = Δτ
RMS
For many links, the DGD values are randomly distributed closely as a Maxwell distribution.
Under the assumption of a perfect fit with a Maxwell distribution, the linkage between the two
metrics, linear average DGD and RMS DGD is given by Equation (1c).
1/ 2
8
2 1/ 2
(1c)
< Δτ > = < Δτ >
3π
NOTE 1 Equation (1c) applies if the distribution of DGD values is Maxwellian. This assumption may not be valid if
there are highly birefringent elements (relative to the rest of the link) in the optical path. A multiplier of from 3 to
3,7 (see IEC 61282-3), depending on probability limits accepted by the link owner, is applied to the PMD value
AVG
to determine the maximum DGD, which is specified for ITU-T compliant links. This multiplier is based on a Maxwell
assumption and reflects a very long tail of that distribution. If the link includes a highly birefringent element, both
the PMD and PMD metrics will increase relative to the actual tail of the DGD distribution (implying that a
AVG RMS
reduced multiplier could be used), but Equation (1c) may not be maintained because the DGD distribution will
begin to resemble one based on the square root of a non-central chi-square distribution with three degrees of
freedom. In these cases, the PMD value will generally be larger relative to the PMD value indicated by
RMS AVG
Equation (1c). This condition is indicated by “flat tops” on the fringe envelopes from the time domain measurement
methods such as Method C and by bimodal DGD distributions from the frequency domain measurement methods
such as Method B.
The expected value operator in the above equations refers to the long term expected value
across all wavelengths. In practice, a finite wavelength range at a particular point of time and
condition are sampled and some form of mean of the data is calculated. The expected value
of these calculated means is equal to the long-term expected values, assuming ergodicity
over time, wavelength, and condition. If this assumption is not valid, the result will vary
depending on the particular wavelengths that are sampled. For ergodic conditions, the
6)
.
reproducibility of the measurement will vary with wavelength range and PMD level [3]
NOTE 2 Ergodic: of or relating to a process in which every sequence or sizable sample is equally representative
of the whole.
5 Measurement methods
5.1 Methods of measuring PMD
Six basic methods of measuring PMD are given. Details specific to each are given in
normative annexes. The methods are listed below in order of their introduction. For some
methods, multiple approaches of analyzing the measured results are also provided.
___________
6)
Figures in square brackets refer to the bibliography.
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61280-4-4 IEC:2006 – 19 –
Method A Fixed analyzer (FA)
• Fourier transform (FT)
Method B Stokes parameter evaluation (SPE)
• Jones matrix eigenanalysis (JME)
• Poincaré sphere analysis (PSA)
Method C Interferometry (INTY)
• Traditional analysis (TINTY)
• General analysis (GINTY)
Method D Stokes parameter evaluation using back-reflected light
• Jones matrix eigenanalysis (JME)
• Poincaré sphere analysis (PSA)
Method E Modulated phase-shift
• Full search
• Mueller set analysis
Method F Polarization phase shift (PPS)
Each method has advantages in certain respects and disadvantages in others. For example:
Methods A, B, D, E and F may rely on measurements that can be disrupted if the link is
vibrating such as in the case of aerial cables if the optical properties of the fibre change within
the time used to measure the data for calculating individual DGD values. Fast measurement
rates have been implemented in some commercial field test systems to reduce t
...
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